Liquid clarification apparatus



6, 1941. A. J. FISCHER LIQUID CLARIFICATION APPARATUS Original Filed Dec; 15, 1957 JNVENTORS mam ATTORNEY.

=- swarms r LIQUID 6 A'EUS Anthony J. Fischer, Flushing, N. Y., assignor to The Dorr Company, Inc, New York, N. Y., a

corporation of Delaware Original application December 15, 1937, Serial No. 179,814, now Patent No. 2,233,448, dated March 4, 1941. Divided and this application April 6, 1940, Serial No. 328,294 I 7 Giaims.

In the field of clarifying organically polluted liquids such as sewage, trade wastes and the like, there is often used today flocculation followed by clarification or, as it is sometimes called, sedimentation. This invention relates to a novel arrangement in the same tank or basin of a aw culation zone and a sedimentation zone wherein features of advantage lie in the design and relationship of parts thereof.

1,893,451, and- .in the patent to Darby, No. 2.089.160. the latter being an improvement on the former. The type of traveling sediment or sludge impell ng rakes. blades. or flights mainly proposed for sweeping the floor area or areas of the sedimentation, zone clean of sludge accumulation may be considered blades or flights moved in closed paths about generally horizontal axes, so that sections of the closed paths are substantiallyhorizontal. Such mechanisms are exemplified V by what are called scraper conveyors, namely, 55

two or more endless belts or chains taking around sprockets with flights or blades extending transversely from one chain to the other.

. The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional features, objects and advantages thereof, will be The polluted organic matter is suspended in 10 best understood from the following description of the liquid. Most of it is settleable as sediment in the illustrated specific embodiments thereof the form of sludge, if the liquid be held in quiwhen read in connection with the accompanying escence as in a sedimentation zone or clarifier. drawing, in which- But a quantity of these suspended solids is so Fig. 1 shows a plan view of the flocculatorsmall as to be colloidal and therefore dimcult to 1 clarifier unit; settle. Flocculation has lately been resorted to Fig. 2 shows a longitudinal sectional elevation ahead of sedimentation for coagmenting or of the unit; amassing suspended matterinto flocs or fioc 001- Fig. 3 is a vertical cross-sectional view taken onies and conditioning them as to denseness to as on the plane indicated by the line 3-3 of Fig. make them more readily susceptible to settling 1 and it typifies a bolt securing construction by in a classifier, along with the suspended solids whichv certain ofthe overflow weirs are held in that, are normally settleable. By causing the flocs vertically adjusted positions; and to meander in theliquid, there is a tendency for Fig. 4 is a view illustrating in elevation a boltthe does to entrap and adsorb other fine solids securing means holding one of the overflow weirs that may escape direct fiocculating treatment. in vertically adjusted position.

The flocs thus formed are fragile and easily This application is a division of my parent apdisintegrated so they must be treated gently, for plication Serial No. 179,814, filed December 15. it once disintegrated they are dimcult of re-fioc- 1937 which matured into Patent No. 2,233,448, culation. Therefore, it is important that the March 4, 1941 and said Figures 1 and 2 hereof fioc-laden liquid be drifted or passed as unmoare a reproduction of Figures 1 and 2 of the above lestedly as possible from the flocculation zone to identified parent application. The embodiment the sedimentation zonen of the invention illustrated by said figures has a Again, as a major part of these flocs comprises flocculation zone with fiocculating mechanism organic matter that is putrescible and subject to operable therein on the one hand and a succeedbecoming septic, bottom or floor sweeping must ing sedimentation zone with sediment-raking be provided in the sedimentation zone for conmechanism operable therein on the other hand tinually raking or impelling to discharge the sedand may be said to be characterized by the horiiment or sludge resulting from the sedimentation zontal juxtaposition and novel arrangement of of fioc-laden liquid. That is, care must be taken the flocculation zone and functioning instruto avoid accumulations of organic solids if sepmentalities thereof with reference to the horitic conditions are to be avoided in the apparatus. zontal succeeding sedimentation zone and func- The fiocculating bladed means generally protioning instrumentalities thereof. posed for use in the combination apparatus may Referring to the drawing, ill designates the he found described in the patent to Smith, No. tank or basin of rectangular or oblong form and composed of vertical side walls II and I2, vertical end walls I 3 and ll,-and the bottom composed of sections i5 and. I 6 inclined slightly towards their adiacent ends and connected thereat by a. sedimentation receiving sump. The section l5 of the bottom of the tank or basin inclines down wardly from the lower edge of the front or influent inlet end of the fioc'culator-clarifler unit to the sump l1, .and the rear section It of the bottom of said unit inclines downwardly from the rear end wall ll of the unit to the sump II which is disposed transversely of the tank or basin. The sump extends entirely across the tank or basin and is provided with a sediment or sludge discharge pipe ll having a control valve is.

The front end wall ll is provided at the upper portion with an influent inlet or feed pipe 20, and the front section or portion of the tank or basin lying above the section I! of the bottom of the same and above the sump l'l constitutes.

a flocculation zone, while the remainder of the tank or basin constitutes a sedimentation zone which is preferably provided with a sediment collecting tray 2| that is in effect a horizontal partial partition for forming a duplex sedimentation zone having superposed sedimentation collecting floor areas. The flocculator is placed ahead of the clarifler tray 2| and the upper portion of the flocculation zone is divided into separate compartments 22 by vertical transverse partial partitions or bailies 23, 24 and 25 extending entirely across the tank and downwardly from the upper edges of the side walls of the tank to a point approximately midway between the top and bottom of the tank. The bafiles or partitions, which may be of any desired size and number, materially contribute to the control of the flow of liquid andquiescent condition of the flocculation zone, so that the movable blade flocculation means for coagmenting suspended material into settleable flocs may effect agitation to drift floc-laden liquid into the sedimentation zone without causing agitation sufllcient to disintegrate the floc colonies formed in the flocculation zone.

The movable bladed flocculation mechanism comprises a plurality of paddles or blades 28 and 21 arranged in groups and extending transversely of the flocculation zone of the tank. The groups of blades or paddles 28 and 21 are mounted on shafts 28 and 29 which are journaled in suitable bearings in the side walls of the tank. Each of the shafts 28 and 29 carries three groups of blades or paddles which are located adjacent the side walls of the tank and centrally thereof, that is, midway between the side walls of the tank, but any number of groups of blades or paddles may, of course, be provided for each of the shafts and any number of shafts and paddles may be employed to suit the dimensions of the flocculator. Theblades or. paddles 28 are connected with the shaft 28 by arms or members 30, and the blades or paddles 21 are connected with the shaft 29 by similar arms or members 3i.

. The blades of the side groups of each shaft are disposed in alignment, while the blades of the central group of each shaft are staggered with relation to the blades of the side groups. Any suitable means may be provided for rotating the shafts in the required speed to effect coagmentation oi the suspended material into settleable flocs. The paddles or blades rotate in the direction of the arrows in Fig. 2 of the drawing, and the groups of blades or paddles operate in the lower portion of the flocculation zone. and each paddle or blade during a portion of its revolution extends into one or the other of the compartments-22 and sweeps across the bottom of such space or compartment, as clearly illustrated in Fig. 2 of the drawing. The blades move slowly through the lower portion of the flocculation zone, and the suspended material is caused to collect into settleable flocs of suflicient density to settle upon the sediment collecting tray or the bottom floor of the sedimentation zone when they are drifted into the same.

The sediment collecting tray which is disposed sediment or sludge swept, scraped or raked from the tray 2| which constitutes an upper sludge collecting floor area. The means for scraping or raking sludge or sediment from the superposed floor areas formed by the tray and the section It of the bottom of the tank comprises spaced endless belts or chains 23, 34 and SI arranged on front and rear sprocket wheels 36, 31, SI and a 39 and connected by transversely disposed blades or flights 40 which extend substantially entirely across the tank, so as to scrape or rake the entire upper surface of the tray 2| and the section II of the bottom of the tank. The blades III are connected intermediate or their longitudinal edges to the endless drag chains or belts, and one longitudinal edge of each of the blades scrapes or rakes the tray and the other longitudinal edge of each of the blades rakes or scrapes the section iii of the bottom of the tank, as

clearly illustrated in Fig. 2 of the drawing. The sprocket wheels 36. 31, 38 and are mounted 'on horizontal shafts 4|, l2, II and M, and they are spaced apart in vertical and substantially horizontal alignment so that the blades or flights ll travel in a closed path encircling the sediment collecting tray and having vertical and horizontal sections for impelling sediment to the sump i! and the sediment discharge outlet ll. The flights or blades at the upper portion of the endless conveyor or scraper formed by said blades and chains pass over the tray in a direction concurrently with the flow through the tank, and the blades or flights at the lower portion of the endless scraper or conveyor travel over the section it of the bottom of the tank countercurrently to the flow of liquid in the tank. The blades or flights 40 continually scrape from the tray and the section I 6 of the bottom of the tank, sediment or sludge accumulating on such floor areas, and by this continual removal of the sedi ment or sludge and the impelling of the same to the discharge outlet prevent any putrescible material from accumulating and producing septic conditions. While three endless chains or belts are shown in the illustrated embodiment of the invention, any desired number of chains or belts and blades or flights may be employed according to the dimensions of the tank or basin.

The flocs formed in the flocculation section or zone of the unit are drifted into the sedimentation zone without turbulence and while in the flocculation zone are caused to meander sufficiently in the liquid to form floc colonies of sufficient size and density to be settleable with the normally settleable material when the same reach the sedimentation zone. The sediment collecting tray forms a duplex sedimentation zone, and the sediment or sludge accumulating on the tray and on the floor of the sedimentation section of the unit is continually removed therefrom and impelled toward the sump l1 and the discharge outlet thereof. As any suitable means may be provided for actuating the endless scraper conveyor, illustration thereof is believed unnecessary.

The supernatant liquid or eiiluent is removed from the unit at the sedimentation zone by means of side outlet openings formed in the side walls ii' and I2 and communicating with launders '55 extending longitudinally of the tank or basin at the ciarifler section thereof and connected at the rear end of the unit by a transverse launder 81. The eiiiuent passing through the outlet openings 65 flows over a weir 58 located in the launders and comprising longitudinal side portions 65 and a transverse connecting portion 55. The longitudinal and transverse portions 59 and B of the weir 58 are adjustable vertically to assist in controlling the level of the liquid within the tank or basin, but complete control'of the level of the liquid is obtained by means of a vertically adjustable weir 5| located at the center of the outer wall of the transverse launder 41 at an eilluent outlet opening 52. Figs. 3 and 4 are views illustrating a type of securing means by which the overflow weirs such as 49, 50 and Si are rendered vertically adjustable and are held in verticallyadjusted position, to wit, by bolts such as 4911 or 5m that pass through slotted portions provided in the overflow weirsecured thereby, as for example, in overflow weir 49, 50. or 5|, as the case may be. The transverse launder is provided with an efliuent tank or receptacle 55, from which extends an eflluent discharge pipe 54 and with which is also connected a longitudinal eiiiuent conducting pipe 55 extending along one side of the clarifier section of the tank or basin andconnected to aplurality of transversely disposed emuent outlet pipes 56 located beneath the sediment collecting tray and adapted to permit clarified supernatant liquid or etliuent to' flow from the tank orv basin at spaced points below said tray. The transverse eiiiuent outlet pipes 55 are provided at opposite sides with suitable apertures 51 through which the efiiuent may flow, as indicated .by the arrows in Fig. 2 of the drawing.

While three transverse emuent outlet pipes 58 are illustrated, the number may, of course, be varied. The eflluent conducting pipe extends horizontally from the innermost transverse pipe to a point beyond the rear end of the tank or basin and is then extended transversely to a point below the eilluent outlet tank or receptacle 53, and it has an approximate vertical portion which extends through the bottom of said outlet tank or receptacle'53. The upturned portion of pipe 55 has' the vertical height or level of its overflow oroutlet made adjustable by means of a plurality of removable tubular rings 55a that are arranged to flt one on another. As the outlet pipes 56 are shown to merge into pipe 55, the adjustment of the vertical height of the terminal 55a of pipe 55, tends to control the outflow through all of the pipes 55.

The particular arrangement of the sediment collecting tray and the chain drag endless scraper or conveyor renders the clarifier section of the unit particularly susceptible for removal of scum from the liquid by skimming, and the tank or basin is provided at the rear or efliuent discharge end with a. transverse trough 58 located interiorly of the sediment or clarifler' section of the tank or basin at the rear wall thereof adjacent the transverse launder 41 and consisting of a bottom wall 59 and an inner side wall 60 having its upper edge located substantially at the level of the liquid within the tank or basin. The inner wall of the transverse launder 51 forms one of the side walls of the trough 5B and any suitable means may be employed for the removal of scum from the trough, and such removal may be effected without any material effect on the quiescent condition of the liquid within the sedimentation zone or section of the tank or basin. In the operation of the flocculator-claiifier unit, the normally colloidal or non-settleable solids are rendered settleable in the flocculation zone by forming floc nuclei, and these are subjected to mechanical agitation of the movable flow of liquid through the tank or basin and will be conditioned into settleable size mechanically by the movable bladed flocculation means. The flocs are fragile and easily disintegrable, and when once disintegrated are diilicult to re-flocculate. The slowagltation of the liquid within the flocculation zone causes the flocs to be conditioned without danger of disintegration and the slow drift of the floc-laden liquid directly to the clarlfler or sedimentation zone transfers the flocs from the flocculator or clarifler without disintegration. Also as the flocs are largely of organic material, they will spoil or go septic unless kept continually in motion and passed out of the unit promptly. The motor actuated flights or sludge scraping blades sweep sediment along the upper floor area formed by the tray and along the bottom of the sedimentation section of the tank, impelling the sludge-to the discharge outtageously employed for treating raw sewage or at I any stage of sewage treatment where flocculation followed by sedimentation is desirable.

I claim:

1. Apparatus for clarifying liquids comprisinga tank having in horizontal sequence a flocculation zone and a sedimentation zone in hydraulic communication with each other, influent means for incoming feed to the flocculation zone, bladed agitating means operable in repetitive paths in the flocculation zone at a speed suflicient to effect coagmentation of suspended material into I settleable flocs, the doc-laden liquid being adapted to drift with the liquid from the flocculation zone into the sedimentation zone, a horizontal partition in the sedimentation zone representing a settling area which is superposed upon and spaced from the settling area represented by the tank bottom, both said settling areas corresponding to an upper and a. lower settling zone respectively, impelling means for moving sediment from said settling areas to a common point of discharge in the tank, a sediment discharge outlet, outlet means comprising an overflow pipe for clarified supernatant liquid from said lower settling zone, outlet means comprising an overflow weir for clarified liquid from said upper settling zone, and a vertical transverse partition dividing the flocculation zone from the sedimentation zone and extending from a point above the liquid level downwardly into the liquid body to a point at least as low as the settlingsurface of the adjacent end-portion of the horizontal partition, said vertical partition being spaced from said adjacent end portion of the horizontal partition so as to leave an upward passage between them, the lower end of said vertical partition being spaced from the tank ,bottom so as to leave a horizontal flow passage through which the bulk of the floc-laden liquid flows, the,relat ive arrangement of the partitions in the tank being such as to cause one component portion of said tions of the tank, a horizontally-extending partition means extending across the tank and fora substantial length of the sedimentation zone but terminating short of the rear end wall of the tank and functionally dividing the sedimentation zone into upper and lower settling sections, influent means for incoming feed for the flocculation zone, outflow means for conducting clarified supernatant liquid from the upper portion of each of said settling sections of the sedimentation zone, a sediment discharge outlet leading from the lower interior portion of the tank, flocculation means providing movable blades operable in said flocculation zone at speed sumcient for effecting coagmentation of suspended material into settleable flocs and for eflecting agitation suflicient to drift floc-laden liquid whereby a some of the flocs drift into the lower settlim section while other of the flocs drift into the upper settling section of the sedimentation zone, and means providing flights movable in a closed path having an upper horizontal section along which the flights operate within the space above said partition means for moving sediment rearwardly along said partition means and a lower horizontal section along which the flights operate within the space below said partition means for impelling sediment forwardly to said discharge outlet.

3. Apparatus for clarifying organically polluted liquids comprising a tank having in hydraulic communication a flocculation zone and a sedimentation zone horizontally disposed immediately behind the flocculation zone, influent means for distributing feed across the front end of the flocculation zone, a sediment-receiving sump provided in the vicinity'of the rear end of the flocculation zone, the depth of which rear end of the flocculation zone is substantially the same as that of the front end of the sedimentaion zone, a sediment-discharge conduit leading from said sump, means in said flocculation zone for agitating liquid therein, a horizontal transverse partition functionally dividing the sedimentation zone into upper and lower settling sections but terminating ahead of the rear wall of the tank, sludge-conveying flights movable in a closed path about said partition and having rearward horizontal movements above the partition, downward movements past the partition, forward longitudinal movements below the partition and upward movements past the partition and functioning to transfer sedimented material rearwardly above said partition and forwardly below said partition ultimately to said sump, outflow means comprising a horizontally-extending vertically-disposed weir past which supernatant liquid overflows from the rear upper portion of the sedimentation zone and also comprising perforated pipes disposed below the partition and mergingly terminating in an upturned section rising to an elevation approidmately the same as that of said overflow weir, and a transverse banle extending across the rear end portion of the flocculation zone and downwardly from an elevation at least as high as said weir to an elevation approximately that of the partition and spacedly disposed ahead of the front end of said partition sufficiently to permit an unobstructed passage of the sludge conveying flights as they move through the space between said baflie and said partition. j

4. Apparatus for clarifying organically polluted liquids comprising a tank having in hydraulic communication and horizontal serial arrangement a forwardly disposed flocculation zone and a rearwardly disposed sedimentation zone and with respect to which the proximate end portions of said zones are of substantially the same depth, influent means for supplying incoming feed to the forward end portion of the flocculation zone, a sediment discharge outlet leading from the lower interior portion of the tank from the region in the vicinity of the rear end of the flocculation zone and the forward end of the sedimentation zone, flocculation means comprising bladed elements operable at speeds conducive to the development of flocculatable matter into settleable flocs, a tray functionally dividing said sedimentation zone into upper and lower settling sections and provided by a transversely and longitudinally-extending floor member and an apron member depending downwardly from the rear end of said floor member but spaced somewhat ahead of the rear wall of the tank, means providing bladed flights movable in a closed path encircling the tray and arranged whereby the flights scrape sediment rearwardly along the floor section of the partitioning means and scrape sediment forwardly along the bottom of the tank whereby the scraped sediment is ultimately received in the immediate region of said discharge outlet, outflow means for conducting supernatant liquid from said upper settling section, and outflow means for conducting supernatant liquid from that upper portion of said lower settling section which is immediately aheadof the depending apron, at least one of said outflow 'means having a vertically positionable overflow weir whereby the outflowing quantity of supernatant liquid from one of said settling sections relative to the other can be adjusted according to the positioning of said weir.

5. Apparatus for clarifying organically polluted liquids comprising a tank having in hydraulic communication and in longitudinal serial arrangement a forwardly disposed flocculation zone and a rearwardly disposed sedimentation zone of which the bottom of the flocculation zone is at substantially the same elevation as that of the bottom of the sedimentation zone, influent means for delivering incoming feed into the flocculation zone, a sediment-receiving sump provided across the tank bottom in the region at the rear end of the flocculation zone and at the front end of the sedimentation zone, a sediment-discharge conduit leading from said sump, movable bladed flocculation means in said flocculation zone for coagmenting suspended material into settleable flocs and for effecting agitation sufflcient to drift flocculating liquid into the sedimentation zone, a longitudinally and transverse- 1y extendirm sediment collecting tray disposed within the sedimentation zone and dividing the latter in-to vertically disposed settling sections, actuatable flights movable in a closed path extending rearwardly above the tray, thence downwardly past the rear end of the tray, thence forwardly along that portion of the tank bottom below the tray and finally upwardly past the forward end of the tray, supernatant liquid outflow means from the upper settling section of the sedimentation zone, an associated receptacle into which the outflow supernatant passes, and a second outflow means comprising longitudinally spaced transversely extending perforated pipes located below the tray and having a common upflow discharge conduit arranged for discharging eflluent therefrom into the aforesaid receptacle.

6. Apparatus for clarifying organically polluted liquids comprising a tank having in hydraulic communication a flocculation zone and a sedimentation zone, influent means for incoming feed for the flocculation zone, a sediment discharge outlet, movable bladed flocculation means in said flocculation zone for coagmenting suspended material into settleable flocs and for 25 effecting agitation sumcient to drift floc-laden liquid into the sedimentation zone, a sediment collecting horizontal trayin the sedimentation zone vertically spaced from the bottom thereof, longitudinal and transverse launders located at the upper portion of the sedimentation zone and communicating with the interior of the tank for outflow of clarified supernatant liquid, a plurality of longitudinally spaced transversely extending eilluent outflow means located below the tray, a transverse scum receiving trough located at the upper portion of the tank at the rear end thereoiiand actuated flights traveling in a closed path encircling the tray forimpeliing sediment rearwardly along the top of the tray and thereafter forwardly along the tank bottom to said ANTHONY J. FISCHER. 

